Spicules and trabeculae are found in
Lecture 3 part 1
Bone is available in two different architectures. The outer wall of most bones is made up of compact bone, while the inner cavities are made up of trabecular bone. Both forms of bones are represented by a long bone. Trabecular bone occurs as several struts or spicules of bone in the head area or epiphysis of the bone. Around the long bone’s shaft, or diaphysis, there is a dense layer of compact bone.
Long bones also display the two sides of a bone. The periosteal, or outer surface, of the bone is usually protected by a fibrous tissue called periosteum, which is where muscle and tendon bind to bone. The endosteal surface is the inner surface of the bone, which is normally protected by a thin layer of cells called the endosteum.
What is lamina dura? what does lamina dura mean
The parathyroid glands secrete a hormone that increases blood calcium levels by inducing osteoclast bone resorption, facilitating calcium absorption in the intestine, and inhibiting calcium excretion in the urine.
1. Osteoblasts on the deep side of the periosteum deposit osteoid tissue2. Become stuck as the tissue calcifies3. Lay down matrix in layers parallel to the surface4. Form circumferential lamellae over the surface5. Endosteum osteoclasts widen the marrow cavity
Small channels or canals between lacunae that enable osteocytes to exchange wastes and carry in metabolites; osteocytes send out cytoplasmic processes into the canaliculi and communicate with neighboring cells through gap junctions.
Which of the following is NOT a PTH effect?
A) an increase in phosphate levels in the blood
B) Calcium excretion is reduced
C) increased calcium absorption in the intestine
D) an increase in the amount of osteoclastsE) an increase in the synthesis of calcitriol
Which of the following statements more accurately describes cartilage interstitial growth?
A) On the cartilage’s external surface, cartilage-forming cells divide and secrete new matrix. B) Chondroblasts grow from cells in the perichondrium. C) Inside the cartilage, chondrocytes separate and secrete new matrix. D) It emerges from the outside.
Medical document text recognition test
From the rostral (the region around the nose and mouth) to the caudal (the rest of the body), embryonic/fetal development takes place (posterior). Intramembranous ossification is responsible for the formation of the skull and vertebral column. Endochondral ossification produces the long bones of the arms and legs as growth progresses along the body axis.
Intramembranous ossification, unlike the other type of bone formation, endochondral ossification, does not require cartilage. It’s also necessary for the normal healing of bone fractures and the rudimentary formation of the skull’s bones.
The formation of bone spicules (aggregates of bony matrix) is the first step in the process, which leads to the formation of trabeculae. At the surface of trabeculae, the periosteum is formed, and bone growth continues.
Embryonic mesenchymal cells (MSC) condense into layers of primitive connective tissue that are vascularized. Certain mesenchymal cells congregate near or around blood vessels and differentiate into osteogenic cells, which deposit bone matrix on a continuous basis. Separate mesenchymal cells divide into osteoblasts, which line up along the spicule’s surface and secrete more osteoid, causing the spicule to grow in size.
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Intramembranous ossification is one of two important processes that produce rudimentary bone tissue during fetal development of the gnathostome (excluding chondrichthyans such as sharks) skeletal system.
Intramembranous ossification is started by mesenchymal stem cells in the mesenchyme or the medullary cavity of a bone fracture. MSCs, or mesenchymal stem cells, are unspecialized cells that may grow into osteoblasts. A MSC has a small cell body with a few long and thin cell processes; a wide, circular nucleus with a prominent nucleolus surrounded by finely scattered chromatin particles, giving the nucleus a distinct appearance; and a small amount of Golgi apparatus, rough endoplasmic reticulum, mitochondria, and polyribosomes until it begins to grow. Furthermore, except for a few reticular fibrils, the mesenchymal stem cells are widely distributed within an extracellular matrix devoid of all types of collagen. 1st